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It has been observed that, after 2 hours of aerobic exercise, plasma interleukin-6 (IL-6) increases whereas nuclear concentrations of enzyme DNA methyltransferase (DNMT) 3B significantly decreased in peripheral blood mononuclear cells (PBMCs), with no change observed in DNMT3A. The aim of the present study was to detect differences in these changes induced by exercise in plasma IL-6 levels as well as in PBMC nuclear concentrations of DNMT3A and DNMT3B, in relation to age and sex. Four groups were studied: 12 young men (24.8 ± 1.77 years old), 12 young women (23.8 ± 1.81 years old), 12 adult men (45.8 ± 1.82 years old), 12 adult women (mean 44.5 ± 2.07 years old). Participants had to run at 60% of maximal oxygen consumption (VO2max) for 120 minutes, interspersed with sprints at 90% of VO2max for the last 30 seconds of every 10 minutes. About 250 μL of PBMCs (1 × 10 cells) were treated with 100 μL of either pre-exercise plasma or post-exercise plasma and nuclear DNMT3A and DNMT3B concentrations were quantified. No change in nuclear concentration of DNMT3A following the exercise was observed. Conversely, nuclear concentrations of DNMT3B significantly decreased, with a reduction of about 78% in young men, 72% in young women, 61% in adult men, and 53% in adult women. Moreover, a strong positive correlation between the nuclear concentration of DNMT3B in PBMC following stimulation with post-exercise plasma and post-exercise plasma concentrations of IL-6 was observed in all the 4 studied groups. This study confirms that a single bout of endurance exercise is sufficient to decrease nuclear concentrations of DNMT3B and thus protein upregulation. Moreover, the epigenetic mechanisms induced by exercise apparently cause more intense changes in men than in women and that, in both of them, this effect seems to decrease with age.

We examined, on 28 healthy adult subjects, the possible correlations of an exhaustive exercise, and the consequent high blood lactate levels, on immediate (explicit) and delayed (implicit) motor execution of sequential finger movements (cognitive task). Moreover, we determined with transcranial magnetic stimulation whether changes in motor performance are associated with variations in excitability of primary motor area (M1) and supplementary motor area (SMA). We observed that, after an acute exhaustive exercise, the large increase of blood lactate is associated with a significant worsening of both explicit and implicit sequential visuomotor task paradigms, without gender differences. We also found that, at the end of the exhaustive exercise, there is a change of excitability in both M1 and SMA. In particular, the excitability of M1 was increased whereas that of SMA decreased and, also in this case, without gender differences. These results support the idea that an increase of blood lactate after an exhaustive exercise appears to have a protective effect at level of primary cortical areas (as M1), although at the expense of efficiency of adjacent cortical regions (as SMA).

We examined the role of main and external cuneate nuclei neurons in processing sensory information during forelimb passive movement. We recorded activity of neurons using circular and figure-eight trajectories, at different speeds, in anaesthetized rats. A multivariate regression analysis was performed to correlate neural discharge to movement direction and speed, the two components of the velocity vector. We found that the activity of the majority of cuneate neurons related to passive movement velocity and that the directional component of the velocity vector accounted for a larger fraction of the variability in the firing rate than the scalar component (speed). These results indicate that cuneate cells can process whole limb afferent information to elaborate a representation of the movement velocity vector.

The present study was undertaken to analyze the effects on unitary activity of inferior olive (IO) neurons elicited by activation of cerebellar lateral nucleus (LN), in rats submitted to the chronic destruction of MDJ structures, i.e. in animals in which the LN-evoked effects in IO should be depended only on activation of GABAergic cells of LN. It has been observed that about two-thirds of the olivocerebellar neurons are significantly affected by LN stimulation, and > 68% of those cells were inhibited. Two-thirds of the inhibitory responses were compatible with a monosynaptic linkage, whereas the remaining inhibitions were probably due to polisynaptic linkages. The majority of LN-induced inhibitions was abolished or greatly reduced following application of GABA antagonists.

We studied in vitro the effects of anticonvulsant drugs Gabapentin and Topiramate on the production of reactive oxygen species and nitric oxide (NO), the activity of glutamine synthetase (GS), and cell viability in primary cultures of rat cortical astrocytes which are intimately involved in the normal functioning of neurons. We investigated the effects of these drugs at concentrations within the therapeutic range (1, 10 and 50 microg/ml). We observed that, in cultured astrocytes, Gabapentin induced a weak increase in the biosynthesis of NO, a mild decrease in GS activity and cell viability, and minor induction of a stress condition. Topiramate was observed to induce even greater stressor effects on these cells.

Using anesthetized adult rats, we studied the relationships between the activity of cells belonging to the external cuneate nucleus (ECN) and passive forelimb positions. In essence, we sought to distinguish between a representation of limb position based on local limb parameters (individual joint angles, for example) or a representation based on more global parameters such as the length and the orientation of the limb axis. Using multivariate regression analyses we found that most neurons showed strong linear relationships with the length and the orientation of the limb axis. Relationships to individual joint angles were, instead, rather weak and in most cases not significant. This result implies an extensive integration of sensory information at the level of second order sensory neurons.

The cortical input of 117 dentate nucleus neurons projecting either to the red nucleus (73 cells) or to the inferior olive (44 units) was studied electrophysiologically in rats. The majority of cells in both groups responded to electrical stimulation of discrete sites of the contralateral motor cortex. However, activation latencies from the same cortical focus were shorter for neurons projecting to the red nucleus than for olivary-projecting neurons. Principal components analysis pointed out significant differences between the two neuronal subgroups also in the temporal pattern of activity. These results suggest that a motor command might be transmitted through parallel independent channels to cerebellar neurons projecting to different regions of the brainstem.

The present study was carried out to determine whether, in the rat, the electric activation of the projection from the cerebellar lateral nucleus (LN) to the accessory oculomotor nuclei (AON; nucleus of posterior commissure, nucleus of Darkschewitsch, interstitial nucleus of Cajal) is capable of inducing c-fos expression. In particular, we compared the effects of a continuous LN stimulation at low-frequency (tonic stimulation) with those induced by high frequency pulse trains (phasic stimulation). The observed results show that the stimulation of LN induces c-fos expression in a significant proportion of neurones in the contralateral AON. Phasic stimulation was slightly more effective than tonic stimulation in producing c-fos expression.